The spin-on process has been used to planarize and smooth-out pits on the substrate surface in the fabrication of inductive recording heads and magneto-resistive heads. In the past, the spin-on or amorphous procedure has resulted in the film eventually being converted to a near-stoichiometric SiO.sub.2 at high temperatures (&gt;500.degree. C.). The conversion to near-stoichiometric SiO.sub.2 is revealed by the refractive index value of 1.45-1.46 and confirmed by an ESCA analysis.
While the spin-on technique has provided satisfactory dielectric thin film coatings for a substrate surface, none-the-less, a need has been found for dielectric thin film coatings which not only planarize the surface, for example, of a magnetic head, but which have improved hardness and wear resistance parameters.